The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A hard disk drive (HDD) may include a HDD control module (or HDD system-on-a-chip (SOC) controller) with a host interface and a hard disk assembly (HDA) interface. The HDD control module transfers data between the host interface and the HDA interface based on read and/or write command signals received from the host interface. The host interface may be connected to, for example, a computer.
The HDA includes one or more circular platters (i.e. disks), which have magnetic surfaces that are used to store data magnetically. At least one read and write head (hereinafter, “head”) reads data from and writes data on the magnetic surfaces of the disks. The head is mounted on an actuator arm and is moved relative to the disks by an actuator (e.g., a voice coil motor (VCM)).
The HDD control module may include a host interface control module, a buffer management module, and a disk access control module. The host interface control module receives read/write command signals from the host and controls data transfer between the host interface and the buffer management module. The buffer management module stores the data received from the host interface in a buffer prior to being stored on the disks. The buffer management module also stores data received from the disks prior to being transmitted to the host via the host interface. The disk access control module controls data transfer between the buffer management module and the HDA.
A solid-state drive (SSD) may include a SSD control module (or SSD system-on-a-chip (SOC) controller) with a host interface and a solid-state memory (SSM) interface. The SSD control module transfers data between the host interface and SSM via the SSM interface based on read and/or write command signals received from the host interface. The host interface may be connected to, for example, a computer.
The SSM may include, for example, two or more discrete SSM chips. The SSM chips have respective interfaces that communicate with the SSM interface. The SSM interface may include hundreds of input and output (I/O) terminals.
The SSD control module includes a host interface control module, a buffer management module, and a SSM control module. The host interface control module receives read/write command signals from the host and controls data transfer between the host interface and the buffer management module. The buffer management module stores the data received from the host interface in a buffer prior to being stored in the SSM. The buffer management module also stores data received from the SSM prior to being transmitted to the host via the host interface. The SSM control module includes firmware to control access to memory cells of the SSM. The SSM control module controls, for example, read, write and erase operations of the SSM.
An HDD has associated advantages over a SSD. A HDD typically has a larger capacity than a SSD. Also, cost per megabyte (MB) of storage for a HDD is generally less than cost per MB of storage for a SDD. As a SDD includes hundreds of I/O terminals between a SSM control module and SSM, the SSM control module can be complex and expensive relative to a HDD control module. The SSM control module may include complex firmware to control data transfer to and from the SSM.
An SSD has associated advantages over a HDD. A HDD has mechanical components, such as, motors spindles, read/write heads, etc. In contrast, a SSD does not have mechanical moving parts and for this reason does not have an associated risk of a mechanical component failure. In addition, a HDD has slower seek times (time to access a target memory location) than a SSD. A HDD needs to servo a read/write head over a disk to access a target track on the disk. In contrast, a memory cell in a SSD may be directly accessed without servoing a read/write head, which decreases seek time and increases I/O operations per second (IOPs).